Sunday, June 30, 2013

"Planetary nebulae are among my favorite objects in the sky. When a star a bit more massive than the Sun starts to die, it blows off a super solar wind of gas. As it ages more, this wind it blows speeds up, slamming into the stuff previously ejected, carving it into weird and amazing shapes. Eventually, the entire outer layers of the star blow off, exposing the star’s hot, dense core. This floods the surrounding gas with ultraviolet light, causing it to glow."

"Alfred Mitchell-Innes (30 June 1864 – 13 February 1950) was a British diplomat, economist and author. He had the Grand Cross of the Order of Medjidieh conferred upon him by Abbas II, Khedive of Egypt."

"Steel Barrio reconstructs the everyday strategies the working-class Mexican American community adopted to survive in areas from labor to sports to activism. This book links a particular community in South Chicago to broader issues in twentieth-century U.S. history, including race and labor, urban immigration, and the segregation of cities."

"The bid–offer spread (also known as bid–ask or buy–sell spread (in the case of a market maker), and their equivalents using slashes in place of the dashes) for securities (such as stocks, futures contracts, options, or currency pairs) is the difference between the prices quoted (either by a single market maker or in a limit order book) for an immediate sale (offer) and an immediate purchase (bid). The size of the bid-offer spread in a security is one measure of the liquidity of the market and of the size of the transaction cost.[1] If the spread is 0 then it is a frictionless asset."

"An order book is the list of orders (manually and now electronically) that a trading venue (in particular stock exchanges) uses to record the interest of buyers and sellers in a particular financial instrument. A matching engine uses the book to determine which orders can be fulfilled i.e. what trades can be made"

"Electronic trading, sometimes called etrading, is a method of trading securities (such as stocks, and bonds), foreign exchange or financial derivatives electronically. Information technology is used to bring together buyers and sellers through an electronic trading platform and network to create virtual market places such as NASDAQ, NYSE Arca and Globex which are also known as electronic communication networks (ECNs)."

"In finance, an electronic trading platform is a computer system that can be used to place orders for financial products over a network with a financial intermediary. This includes products such as stocks, bonds, currencies, commodities and derivatives with a financial intermediary, such as brokers, market makers, Investment banks or stock exchanges. Such platforms allow electronic trading to be carried out by users from any location and are in contrast to traditional floor trading using open outcry and telephone based trading."

"Electronic trading, sometimes called etrading, is a method of trading securities (such as stocks, and bonds), foreign exchange or financial derivatives electronically. Information technology is used to bring together buyers and sellers through an electronic trading platform and network to create virtual market places such as NASDAQ, NYSE Arca and Globex which are also known as electronic communication networks (ECNs)."

"The Chicago Board of Trade (CBOT), established in 1848, is the world's oldest futures and options exchange[citation needed]. More than 50 different options and futures contracts are traded by over 3,600 CBOT members through open outcry and electronic trading. Volumes at the exchange in 2003 were a record breaking 454 million contracts. On 12 July 2007, the CBOT merged with the Chicago Mercantile Exchange (CME) to form the CME Group, a CME/Chicago Board of Trade Company. CBOT and three other exchanges (CME, NYMEX, and COMEX) now operate as designated contract markets (DCM) of the CME Group.[1]"

"The Chicago Board Options Exchange (NASDAQ: CBOE), located at 400 South LaSalle Street in Chicago, is the largest U.S. options exchange with annual trading volume that hovered around one billion contracts at the end of 2007.[1] CBOE offers options on over 2,200 companies, 22 stock indices, and 140 exchange-traded funds (ETFs)."

"The Black–Scholes /ˌblæk ˈʃoʊlz/[1] or Black–Scholes–Merton model is a mathematical model of a financial market containing certain derivative investment instruments. From the model, one can deduce the Black–Scholes formula, which gives a theoretical estimate of the price of European-style options. The formula led to a boom in options trading and legitimised scientifically the activities of the Chicago Board Options Exchange and other options markets around the world.[2] lt is widely used, although often with adjustments and corrections, by options market participants.[3]:751 Many empirical tests have shown that the Black–Scholes price is "fairly close" to the observed prices, although there are well-known discrepancies such as the "option smile".[3]:770–771"

"A new general and unifying arithmetical concept: The Rational Mean, which allows to generate not only Lucas’s, Bernoulli’s, Newton’s, Halley’s, Householder’s root-approximating algorithms but many new others, also embracing complex roots and the general algebraic equation.
From the evidence at hand, these arithmetical methods have no precedents in the mathematics literature. "

"Israel Moiseevich Gelfand, also written Israïl Moyseyovich Gel'fand, or Izrail M. Gelfand (Yiddish: ישראל געלפֿאַנד, Russian: Изра́иль Моисе́евич Ге́льфанд; 2 September [O.S. 20 August] 1913 – 5 October 2009) was a Soviet mathematician who made major contributions to many branches of mathematics, including group theory, representation theory and functional analysis. The recipient of numerous awards and honors, including the Order of Lenin and the Wolf Prize, he was a Fellow of the Royal Society and a lifelong academic, serving decades as a professor at Moscow State University and, after immigrating to the United States shortly before his 76th birthday, at the Busch Campus of New Jersey's Rutgers University."

"Alexandre Aleksandrovich Kirillov (Russian: Алекса́ндр Алекса́ндрович Кири́ллов, born 1936) is a Soviet and Russian mathematician,[1] renowned for his works in the fields of representation theory, topological groups and Lie groups. In particular he introduced the orbit method[2] into representation theory."

"Victor Ginzburg (born 1957) is a Russian American mathematician who works in representation theory and in noncommutative geometry. He is known for his contributions to geometric representation theory, especially, for his works on representations of quantum groups and Hecke algebras, and on the geometric Langlands program (Satake equivalence of categories). The book "Representation theory and complex geometry", by Chriss and Ginzburg, is nowadays a classical text on geometric representation theory. In an influential paper by Beilinson, Ginzburg, and Soergel, the authors introduced the concept of Koszul duality (cf. Koszul algebra) and the technique of "mixed categories" to representation theory. Ginzburg and Kapranov developed Koszul duality theory for operads."

"Neil A. Chriss is a mathematician, academic, hedge fund manager,[1] philanthropist and a founding board member of the charity organization "Math for America" which seeks to improve math education in the United States.[2] Chriss also serves on the Board of Trustees of the Institute for Advanced Study.[3]"

"For a market impact model, price manipulation and related notions play a role that is similar to the role of arbitrage in a derivatives pricing model. Here, we give a systematic investigation into such regularity issues when orders can be executed both at a traditional exchange and in a dark pool. To this end, we focus on a class of dark-pool models whose market impact at the exchange is described by an Almgren--Chriss model. Conditions for the absence of price manipulation for all Almgren--Chriss models include the absence of temporary cross-venue impact, the presence of full permanent cross-venue impact, and the additional penalization of orders executed in the dark pool. When a particular Almgren--Chriss model has been fixed, we show by a number of examples that the regularity of the dark-pool model hinges in a subtle way on the interplay of all model parameters and on the liquidation time constraint. The paper can also be seen as a case study for the regularity of market impact models in general."

"We have analyzed the regularity of a class of dark-pool extensions of an Almgren–Chriss model and found that such models admit price manipulation strategies unless the model parameters satisfy certain restrictions. The corresponding parameter values will typically diﬀer strongly from values found in empirical analysis or calibration of real-world dark pools. Our results can therefore provide some indication that dark pools may create market ineﬃciencies and disturb the price ﬁnding mechanism of markets."

"At 2:14 PM ET: Stocks are up across the board as advancing issues outpace declining issues on the NYSE by 6.4 to 1. Large- and small-cap stocks are both strong, while the S.&P. 500 index is up 0.69%. Among individual stocks, the top percentage gainers in the S.&P. 500 are Time Warner Cable Inc. and Cablevision Systems Corporation"

"It’s been a rough few months for NYSE Euronext (NYX), owner of the country’s biggest stock exchange. In February, European regulators scrapped its planned $9.5 billion merger with Germany’s Deutsche Börse (DB1) over concerns it would create a monopoly in exchange-traded derivatives. NYSE Euronext’s first-quarter profit tumbled 44 percent, driven by a decline in trading volume. And in April, Facebook announced it would hold the most anticipated initial public offering in years on Nasdaq, NYSE’s arch rival."

"In finance, dark pools of liquidity (also referred to as dark liquidity or simply dark pools or black pools) is trading volume or liquidity that is not openly available to the public.[1] The bulk of these represent large trades by financial institutions that are offered away from public exchanges so that trades are anonymous. The fragmentation of financial trading venues and electronic trading has allowed dark pools to be created, and they are normally accessed through crossing networks or directly between market participants."

"Scott Patterson is an American financial journalist and bestselling author.[1][2] He is a staff reporter at The Wall Street Journal and author of Dark Pools: High-Speed Traders, A.I. Bandits, and the Threat to the Global Financial System and The New York Times bestselling book The Quants.[3][4][5]"

A news-breaking account of the global stock market's subterranean battles, Dark Pools portrays the rise of the "bots"- artificially intelligent systems that execute trades in milliseconds and use the cover of darkness to out-maneuver the humans who've created them.In the beginning was Josh Levine, an idealistic programming genius who dreamed of wresting control of the market from the big exchanges that, again and again, gave the giant institutions an advantage over the little guy. Levine created a computerized trading hub named Island where small traders swapped stocks, and over time his invention morphed into a global electronic stock market that sent trillions in capital through a vast jungle of fiber-optic cables.

By then, the market that Levine had sought to fix had turned upside down, birthing secretive exchanges called dark pools and a new species of trading machines that could think, and that seemed, ominously, to be slipping the control of their human masters.

Dark Pools is the fascinating story of how global markets have been hijacked by trading robots--many so self-directed that humans can't predict what they'll do next.

Tuesday, June 25, 2013

This term there is not an Astronomy session at Waubonsee. I am being considered for a software position in Illinois. I expect a more concentrated effort on problem solving. This post is about the new paper by Maldacena (Institute for Advanced Studies, IAS) and Susskind (Stanford University) on Einstein Rosen bridges, and Einstein, Podolsky, and Rosen states in Quantum Mechanics.

Cool horizons for entangled black holes

(There is a link below to this work)

Einstein produced important ideas while at the IAS, now Juan Maldacena, eighty years or so, later, is coming back to these ideas.

Two quantum states have non-local correlations, some General Relativity solutions also. Maldacena and Susskind try to connect these mathematical facts consistently.

"General relativity contains solutions in which two distant black holes are connected through the interior via a wormhole, or Einstein-Rosen bridge. These solutions can be interpreted as maximally entangled states of two black holes that form a complex EPR pair. We suggest that similar bridges might be present for more general entangled states.

In the case of entangled black holes one can formulate versions of the AMPS(S) paradoxes and resolve them. This suggests possible resolutions of the firewall paradoxes for more general situations."

"WASHINGTON — President Obama will propose a sweeping plan to address climate change on Tuesday, setting ambitious goals and timetables for a series of executive actions to reduce greenhouse gas pollution and prepare the nation for the ravages of a warming planet."

"MOSCOW — President Vladimir V. Putin of Russia offered the first direct confirmation on Tuesday that Edward J. Snowden, the fugitive former American national security contractor, was in an international transit area at a Moscow airport, and he appeared to rule out American requests for his extradition to the United States."

Sunday, June 23, 2013

In this thesis, the QCD sum rules approach has been used to study the nature of the following charmonium resonances: Y(3930), Y(4140), X(4350), Y(4260), Y(4360) and Y(4660). There is a strong evidence that these states have non-conventional (or exotic) hadronic structures since their respective masses and decay channels observed experimentally are inconsistent with expected for a conventional charmonium state. The same phenomenon occurs on the bottomonium sector, where new states like Yb(10890) and Yb(11020) observed recently could indicate the existence of new bottomonium exotic states. In this way, one verifies that the Y(4140) state could be described as a D*sD*s (0++) molecular state or even as a mixture of D*sD*s (0++) and D*D* (0++) molecular states. For the Y(3930) and X(4350) states, both cannot be described as a D*D* (0++) and D*sD*s0 (1-+), respectively. From the sum rule point of view, the Y(4660) state could be described as a \psi' f0(980) molecular state. The extension to the bottomonium sector is done in a straightforward way to demonstrate that the \Upsilon' f0(980) molecular state is a good candidate for describing the structure of the Yb(10890) state. In the following, one estimates the mass of the exotic Bc-like molecular states using the sum rule approach, where these new exotic states would correspond to bound states of D(*) and B(*) mesons. All of these mass predictions could (or not) be checked in a near future experiments at LHC. A large study using the Double Ratio of Sum Rules approach has been evaluated for studying the heavy baryon masses in QCD. The obtained results for the unobserved heavy baryons, with one (Qqq) and two (QQq) heavy quarks will be an excellent test for the capability of the sum rule approach in predicting their masses.

"It’s been over half a century since Frank Drake developed an equation to estimate the probability of finding intelligent life in our galaxy. We’ve learned a lot since then, prompting an astrophysicist from MIT to come up with her own take on the equation. Here’s how the new formula works — and how it could help in the search for alien life."

Saturday, June 22, 2013

Noel Geoffrey Parker (born 25 December 1943) is a British historian specializing in Spanish and military history of the early modern era. His best known book is Military Revolution: Military Innovation and the Rise of the West, 1500-1800, first published by Cambridge University Press in 1988. Born in Nottingham, England, he is a fellow of the British Academy and holds his BA, MA, Ph.D. and Litt.D. degrees from Cambridge University where he studied under the historian Sir John Huxtable Elliott. Amongst the foreign honours he holds, he is a member of the Order of Alfonso X the Wise and was granted the Great Cross of the Order of Isabella the Catholic by the Spanish government. He has received honorary doctorates from the Catholic University of Brussels (Belgium) and the University of Burgos (Spain). He is a fellow of the British Academy, the Spanish Real Academia de la Historia, and the Royal Netherlands Academy of Sciences. In 2012 he was awarded the Dr. A.H. Heineken Prize for History by the Royal Netherlands Academy of Arts and Sciences for his outstanding scholarship on the social, political and military history of Europe between 1500 and 1650, in particular Spain, Philip II, and the Dutch Revolt; for his contribution to military history in general; and for his research on the role of climate in world history.[1]'via Blog this'

Revolutions, droughts, famines, invasions, wars, regicides – the calamities of the mid-seventeenth century were not only unprecedented, they were agonisingly widespread. A global crisis extended from England to Japan, and from the Russian Empire to sub-Saharan Africa. North and South America, too, suffered turbulence. The distinguished historian Geoffrey Parker examines first-hand accounts of men and women throughout the world describing what they saw and suffered during a sequence of political, economic and social crises that stretched from 1618 to the 1680s. Parker also deploys scientific evidence concerning climate conditions of the period, and his use of ‘natural’ as well as ‘human’ archives transforms our understanding of the World Crisis. Changes in the prevailing weather patterns during the 1640s and 1650s – longer and harsher winters, and cooler and wetter summers – disrupted growing seasons, causing dearth, malnutrition, and disease, along with more deaths and fewer births. Some contemporaries estimated that one-third of the world died, and much of the surviving historical evidence supports their pessimism.

Parker’s demonstration of the link between climate change and worldwide catastrophe 350 years ago stands as an extraordinary historical achievement. And the contemporary implications of his study are equally important: are we at all prepared today for the catastrophes that climate change could bring tomorrow?

Friday, June 21, 2013

"Kenneth G. Wilson, who was awarded the 1982 Nobel Prize in Physics for showing how to calculate tricky moments like when ice melts or an iron bar loses its magnetism, died on Saturday in Saco, Me. He was 77."

Wednesday, June 19, 2013

"WASHINGTON — President Obama is preparing a major policy push on climate change, including, for the first time, limits on greenhouse gas emissions from new and existing power plants, as well as expanded renewable energy development on public lands and an accelerated effort on energy efficiency in buildings and equipment, senior officials said Wednesday."

"The cross section for $e^+ e^- \to \pi^+ \pi^- J/\psi$ between 3.8 GeV and 5.5 GeV is measured with a 967 fb$^{-1}$ data sample collected by the Belle detector at or near the $\Upsilon(nS)$ ($n = 1,\ 2,\ ...,\ 5$) resonances. The Y(4260) state is observed, and its resonance parameters are determined. In addition, an excess of $\pi^+ \pi^- J/\psi$ production around 4 GeV is observed. This feature can be described by a Breit-Wigner parameterization with properties that are consistent with the Y(4008) state that was previously reported by Belle. In a study of $Y(4260) \to \pi^+ \pi^- J/\psi$ decays, a structure is observed in the $M(\pi^\pm\jpsi)$ mass spectrum with $5.2\sigma$ significance, with mass $M=(3894.5\pm 6.6\pm 4.5) {\rm MeV}/c^2$ and width $\Gamma=(63\pm 24\pm 26)$ MeV/$c^{2}$, where the errors are statistical and systematic, respectively. This structure can be interpreted as a new charged charmonium-like state."

"With a sample of 225.3 million $J/\psi$ events taken with the BESIII detector, the decay $J/\psi\rightarrow \gamma 3(\pi^+\pi^-)$ is analyzed. A structure at 1.84 GeV/c$^2$ is observed in the $3(\pi^+\pi^-)$ invariant mass spectrum with a statistical significance of 7.6$\sigma$ . The mass and width are measured to be $M=1842.2\pm 4.2^{+7.1}_{-2.6}$ MeV/c$^2$ and $\Gamma=83\pm 14 \pm 11$ MeV. The product branching fraction is determined to be $B(J/\psi\rightarrow\gamma X(1840))\times B(X(1840)\rightarrow 3(\pi^+\pi^-))=(2.44\pm0.36^{+0.60}_{-0.74})\times 10^{-5}$. No $\eta^\prime$ signals are observed in the $3(\pi^+\pi^-)$ invariant mass spectrum, and the upper limit of the branching fraction for the decay $\eta^\prime\rightarrow 3(\pi^+\pi^-)$ is set to be $3.1\times10^{-5}$ at a 90% confidence level."

My daughter is tired of hearing me say: The Chinese are coming, the Chinese are coming!

Well here they are!

Below you could read reports on the .

After the predecessors of the Tea Party, killed the Superconductor Super Collider at Waxahachie, Tex; the US has not built any high energy machine which could do first rate discoveries, like BEPC II in Beijing.

on Mar.31, a group of international scientists working with the Beijing Spectrometer III (BES III) announced that they may have detected a new subatomic particle.
They began specialized studies on the anomalous "Y(4260)" particle. As a striking and unexpected first observation from these new studies, the Y(4260) particle decays to a new, and perhaps even more mysterious, particle named the "Zc(3900)", the collaboration reported ."

"The Zc(3900) is a subatomic particle, a hadron that is believed to be either the first tetraquark or hadron molecule that has been observed experimentally. The discovery was made in 2013 by two independent research groups: one part of the Belle experiment group at the Japanese KEK particle physics laboratory, the other using the BES III detector at the Beijing Electron Positron Collider.[1][2][3][4]

The Zc(3900) is a decay product of the previously observed anomalous Y(4260) particle.[5] The Zc(3900) in turn decays into a charged pion and J/ψ, which is consistent with it containing four or more quarks.[4]
Researchers are expected to run decay experiments this year to determine its nature with more precision."

"The BES III Collaboration has reported observation of a resonance, which they call Zc(3900), which decays into J/\psi + a charged pion. This charged state was observed as an intermediate resonance in their analysis of e+e- annihilations into J/psi + pi+pi- at sqrt(s)=4260 MeV, the peak of the vector state Y(4260). We observe this charged state, Zc(3900), at a 6 sigma significance level in the analysis of 586 pb-1 of data taken with the CLEO-c detector at psi(4160). Our results, M(Z)=3885+-5(stat)+-1(syst) MeV, Gamma(Zc)=34+-12(stat)+-4(syst) MeV, and R=sigma(e+e- -> pi-+ Zc+-(3900))/sigma(e+e- -> pi+pi- J/psi)=(35+-11)% are in good agreement with those reported by BES III. We also present evidence for the observation of the neutral Zc0(3900) at a 3 sigma level of significance with parameters in agreement with those of Zc+-(3900). Because our observations are made at the peak of the 2 3D1 state of charmonium, we do not find any reason to attribute any unconventional properties to the initial state formed by the e+e- annihilations."

Determination of the explosion type of supernova remnants (SNRs) can be challenging, as SNRs are hundreds to thousands of years old and supernovae (SNe) are classified based on spectral properties days after explosion. Previous studies of thermal X-ray emission from Milky Way and Large Magellanic Cloud (LMC) SNRs have shown that Type Ia and core-collapse (CC) SNRs have statistically different symmetries, and thus these sources can be typed based on their X-ray morphologies. In this paper, we extend the same technique, a multipole expansion technique using power ratios, to infrared (IR) images of SNRs to test whether they can be typed using the symmetry of their warm dust emission as well. We analyzed archival Spitzer Space Telescope Multiband Imaging Photometer (MIPS) 24 micron observations of the previously used X-ray sample, and we find that the two classes of SNRs separate according to their IR morphologies. The Type Ia SNRs are statistically more circular and mirror symmetric than the CC SNRs, likely due to the different circumstellar environments and explosion geometries of the progenitors. Broadly, our work indicates that the IR emission retains information of the explosive origins of the SNR and offers a new method to type SNRs based on IR morphology.'via Blog this'

Sunday, June 16, 2013

"We examine the validity of fluctuation-dissipation relations in isolated quantum systems taken out of equilibrium by a sudden quench. We focus on the dynamics of trapped hard-core bosons in one-dimensional lattices with dipolar interactions whose strength is changed during the quench. We find that fluctuation-dissipation relations hold if the system is nonintegrable after the quench. They also hold if the system is integrable after the quench if the initial state is an equilibrium state of a nonintegrable Hamiltonian. However, they fail if the system is integrable both before and after quenching"

We consider the mutual Renyi information I^n(A,B)=S^n_A+S^n_B-S^n_{AUB} of disjoint compact spatial regions A and B in the ground state of a d+1-dimensional conformal field theory (CFT), in the limit when the separation r between A and B is much greater than their sizes R_{A,B}. We show that in general I^n(A,B)\sim C^n_AC^n_B(R_AR_B/r^2)^a, where a the smallest sum of the scaling dimensions of operators whose product has the quantum numbers of the vacuum, and the constants C^n_{A,B} depend only on the shape of the regions and universal data of the CFT. For a free massless scalar field, where 2x=d-1, we show that C^2_AR_A^{d-1} is proportional to the capacitance of a thin conducting slab in the shape of A in d+1-dimensional electrostatics, and give explicit formulae for this when A is the interior of a sphere S^{d-1} or an ellipsoid. For spherical regions in d=2 and 3 we obtain explicit results for C^n for all n and hence for the leading term in the mutual information by taking n->1. We also compute a universal logarithmic correction to the area law for the Renyi entropies of a single spherical region for a scalar field theory with a small mass.

"We study models where the gauge coupling constants, masses, etc are functions of some conserved charge in the universe. We first consider the standard Dirac action, but where the mass and the electromagnetic coupling constant are a function of the charge in the universe and afterwards extend this scalar fields. For Dirac field in the flat space formulation, the formalism is not manifestly Lorentz invariant, however Lorentz invariance can be restored by performing a phase transformation of the Dirac field. In the case where scalar field are considered, there is the new feature that an initial condition for the scalar field is derived from the action. In the case of the Higgs field, the initial condition require, that the universe be at the false vacuum state at a certain time slice, which is quite important for inflation scenarios. Also false vacuum branes will be studied in a similar approach. We discuss also the use of "spoiling terms", that violate gauge invariant to introduce these initial condition."

"The phenomenologically observed flatness - or near flatness - of spacetime cannot be understood as emerging from continuum Planck (or sub-Planck) scales using known physics. Using dimensional arguments it is demonstrated that any immaginable action will lead to Christoffel symbols that are chaotic. We put forward new physics in the form of fundamental fields that spontaneously break translational invariance. Using these new fields as coordinates we define the metric in such a way that the Riemann tensor vanishes identically as a Bianchi identity. Hence the new fundamental fields define a flat space. General relativity with curvature is recovered as an effective theory at larger scales at which crystal defects in the form of disclinations come into play as the sources of curvature."

"Dennis MacAlistair Ritchie (September 9, 1941 – c. October 12, 2011)[1][2][3][4] was an American computer scientist who "helped shape the digital era."[1] He created the C programming language and, with long-time colleague Ken Thompson, the Unix operating system.[1] Ritchie and Thompson received the Turing Award from the ACM in 1983, the Hamming Medal from the IEEE in 1990 and the National Medal of Technology from President Clinton in 1999. Ritchie was the head of Lucent Technologies System Software Research Department when he retired in 2007. He was the 'R' in K&R C and commonly known by his username dmr."

Thursday, June 13, 2013

Aims. We analyze the population of periodic variable stars in the open cluster NGC 3766 based on a 7-year multi-band monitoring campaign conducted on the 1.2 m Swiss Euler telescope at La Silla, Chili. Methods. The data reduction, light curve cleaning and period search procedures, combined with the long observation time line, allow us to detect variability amplitudes down to the milli-magnitude level. The variability properties are complemented with the positions in the color-magnitude and color-color diagrams to classify periodic variable stars into distinct variability types. Results. We find a large population (36 stars) of new variable stars between the red edge of slowly pulsating B (SPB) stars and the blue edge of delta Sct stars, a region in the Hertzsprung-Russell (HR) diagram where no pulsation is predicted to occur based on standard stellar models. The bulk of their periods ranges from 0.1 to 0.7 d, with amplitudes between 1 and 4 mmag for the majority of them. About 20% of stars in that region of the HR diagram are found to be variable, but the number of members of this new group is expected to be higher, with amplitudes below our milli-magnitude detection limit. The properties of this new group of variable stars are summarized, and arguments set forth in favor of a pulsation origin of the variability, with g-modes sustained by stellar rotation. Potential members of this new class of low-amplitude periodic (most probably pulsating) A and late-B variables in the literature are discussed. We additionally identify 16 eclipsing binary, 13 SPB, 14 delta Sct and 12 gamma Dor candidates, as well as 72 fainter periodic variables. All are new discoveries. Conclusions. We encourage to search for the existence of this new class of variables in other young open clusters, especially in those hosting a rich population of Be stars."We encourage searching for this new class of variables in other young open clusters. That there are so many candidates for this new class in NGC 3766 may be analogous to the large number of Be stars observed in this cluster. This would be understandable if both phenomena are indeed related to high rotational velocities characterizing the stellar population of the cluster. If this is true, then the search would be the most efficient in other clusters that are already known to have rich populations of Be stars as well. Variables of this new class may, for example, already be present in the data of NGC 884 gathered by Saesen et al. (2010) for NGC 884.Finally, we propose (Sect. 7.4) the name of ‘low amplitude periodic (or pulsating) A and late-B variables’ for this new class of variable stars."

Monday, June 10, 2013

Published: June 10, 2013

Cosmic hearts started beating a little faster last fall when a team of European astronomers announced that they had found a planet with a mass comparable to Earth’s orbiting Alpha Centauri B, part of a triple star that is the Sun’s nearest neighbor, only 4.4 light years from here.

As Geoffrey W. Marcy, an astronomer at the University of California, Berkeley, said at the time, “This is close enough you can almost spit there.” Close enough, some astronomers said, to send a scientific probe that would get there in our lifetime. The new planet, only four million miles from its home star, would be too hellishly hot for life, but, astronomers said, where there is one planet there are likely to be others, more comfortably situated for life.

Now, however, in a shot across the bow of cosmological optimism, a new analysis of the European data has cast doubt on whether there is actually a “there” there at Alpha Centauri B.

Writing in The Astrophysical Journal last month, Artie P. Hatzes, the director of the Thuringian State Observatory in Tautenburg, Germany, who was not part of the original discovery team, reported that he could not confirm the planet when he went looking for it in the European data on his own. “Sometimes it is there, other times not,” depending on the method he used to reduce the statistical noise, he said in an e-mail.

That doesn’t mean the planet does not exist, Dr. Hatzes wrote, but “in my years of experience in extracting planet signals, this simply does not ‘smell’ like a real planet.”

Xavier Dumusque of the University of Geneva, who led the original discovery effort, said that Dr. Hatzes’s challenge was healthy for science. “Calling to question a detection is always something fruitful,” Dr. Dumusque wrote in an e-mail. But he added that it was clear in his team’s paper that “the signal we are searching for is at the limit of the data precision.”

More data, everyone agrees, is essential, and luckily there will be more data, according to Debra Fischer, a Yale astronomer who has studied the Alpha Centauri system. Both her group and the Geneva team of which Dr. Dumusque is a member obtained more observations in May.

May was a bad time for exoplanet astronomers. NASA’s planet-hunting Kepler satellite lost its pointing capability.

Quoting Jeff Lebowski, the hero of the Coen brothers movie “The Big Lebowski,” Dr. Hatzes said, “Life is indeed ‘gutters and strikes,’ and this week were some gutters.”

The Alpha Centauri B planet is hardly the first promising world to slip into the shadows of uncertainty. Astronomers are still arguing about the existence of Gliese 581g, a “Goldilocks” planet said to be almost a sure bet for life when it was discovered in 2010.

It all goes to show just how devilish the details have become as astronomers close in on the goal of finding Earth-like planets.

Dr. Dumusque and his colleagues first found the planet by the so-called wobble method — perfected over the years by Michel Mayor and his colleagues at the Geneva Observatory — which measures planets’ masses by how much they tug their host star to and fro as they orbit it.

The group uses a specially built spectrograph called Harps on a 140-inch-diameter telescope at the European Southern Observatory in La Silla, Chile, to measure those wobbles, which show up as slight rhythmic shifts in the wavelength of starlight.

The Earth imparts a kick of about four inches a second to the Sun as it orbits around, but that is much smaller than the jitter caused by sunspots and magnetic activity.

The result is that success in detecting low-mass planets depends more and more on digging a small signal out of a much larger background of noise in a reliable manner.

Kepler, which uses the blink method to find planets when they cross in front of their stars, is running up against limits of time.

On the grounds that three blinks were needed to verify an orbit, Kepler’s astronomers once thought they would need three years to verify the existence of planets in comfortable orbits like our own.

But the stars turned out to be noisier than predicted; a year ago, Kepler’s mission was extended so that more blinks could be collected, but the failure of a reaction wheel that allows the telescope to point precisely has probably brought an end to that.

There is still an enormous amount of data in Kepler’s pipeline, including 132 confirmed planets and, as of last week, 3,216 planet candidates.

Waiting in the wings for a 2017 launching is the Transiting Exoplanet Survey Satellite, TESS, which will monitor about two million nearby stars for exoplanets. “In fact,” the project’s leader, George R. Ricker of the Massachusetts Institute of Technology, said during a talk at Google a few years ago, “when starships transporting colonists first depart the solar system, they may well be headed toward a TESS-discovered planet as their new home.”

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One of the worst droughts in this nation’s history, a dry spell that persisted through the early part of this year, has ended with torrential rains this spring that have overwhelmed vast stretches of the country, including much of the farm belt. One result has been flooded acres that have drowned corn and soybean plants, stunted their growth or prevented them from being planted at all.

With fields, dusty and dry one moment, muddy and saturated the next, farmers face a familiar fear — that their crops will not make it.

“This is the worst spring I can remember in my 30 years farming,” said Rob Korff, who plants 3,500 acres of corn and soybeans here in northwestern Missouri. “Just continuous rain, not having an opportunity to plant. It can still be a decent crop, but as far as a good crop or a great crop, that’s not going to happen.”

As farmers go through the ritual of examining every weather map and every tick on the futures boards, trying to divine if and how their pocketbooks can survive another curveball from nature, they are also keeping an eye on Washington, where Congress is still bickering over the farm bill. Farmers are hoping that lawmakers will maintain taxpayer-subsidized crop insurance and other support programs that will help them get through disasters like floods and drought.

Another year of mediocre crop yields could well trickle down to consumers, though agriculture experts insist that it is too early to rule out a robust harvest of corn and soybeans for this year.

“If there’s a shortage of corn and soybeans, and feed costs are higher,” said Bill Northey, the Iowa agriculture secretary, “there’s certainly a possibility that well down the road — six months or a year after that harvest — that you end up seeing higher meat prices than you would have if you’d had a full supply.”

Still, last year’s poor production had only a minor effect on food prices, analysts say, and even with the early planting problems, they expect better yields this year.

Since the beginning of the year, parts of the Mississippi River basin, from eastern Minnesota down through Illinois and Missouri, have received up to three times their normal precipitation. Storm systems also brought flooding to parts of Montana and the Dakotas, and into Nebraska, Iowa and Oklahoma. Iowa, the nation’s top corn producer, had a record 17.66 inches of precipitation this spring.

Just over 44 percent of the country remains in drought, down more than 9 percentage points from the beginning of March.

Ideally, farmers need the top two to four inches of soil to be dry when they are planting so that when they drive their tractors in the field they do not pack down the mud, which prevents the roots from getting oxygen. Oversaturated earth also means that pockets where oxygen can filter through to help the roots breathe will instead be filled with water. Ideally, the moisture should be in the soil directly below the seed.

With rain falling day after day, farmers have been hard pressed to find windows of time when they have dry topsoil to get into their fields to plant. The task has been made harder by lower temperatures and cloudy skies that prevent the land from drying even when it is not raining. Many farmers find themselves more than a month behind in their planting, and some have even given up on planting all their seeds. Late planting could stunt the growth of crops, decreasing production once harvest rolls around.

On May 12, 28 percent of the nation’s corn crop had been planted, compared with 85 percent on the same day last year. As of the United States Department of Agriculture’slatest report, released last week, 91 percent of corn had been planted by June 2, compared with 100 percent a year earlier.

This year, the Agriculture Department had estimated that 97.3 million acres of corn, the most since 1936, would be planted, and that a record 14.14 billion bushels would result from them.

Now, there is concern that “not as much corn was planted as had been indicated,” Joseph W. Glauber, the department’s chief economist, wrote in an e-mail, and “that yields will be adversely affected because plantings were less.”

Mr. Korff, 44, planted all his corn in the middle of May, about a month later than usual, and he has yet to plant any of his soybeans because there has not been a long enough break in the weather, he said. This area about an hour east of Kansas City has already gotten 23.6 inches of rain this year, four inches shy of the total for all of last year.

By this time, three weeks after planting, Mr. Korff said, his corn should be waist high. But instead, his crop looks like rows of small blades of grass, with the plants popping about only four inches out of the ground. The leaves are a pale yellow with brown lesions. Some patches of the field are bald, washed away by the rains. The earth is mucky and chocolate brown in some spots. A narrow stream of water slices through it.

“It doesn’t have the appearance I like to see,” Mr. Korff said.

But on an optimistic note, he said all it would take would be about a week of temperatures in the 80s or 90s and the corn could shoot up.

The rain has benefited some farm operations, however.

“This has been a great spring for cattlemen — just absolutely perfect,” said Kyle Kirby, who has a herd of 2,500 cattle in Liberal, Mo., which has had 29.13 inches of precipitation this year, about a foot more than in the same period last year.

The rain has replenished the pasture grass that cattle eat and has filled the ponds and streams where they drink. During last year’s drought, pastures were a charred brown, and evaporated ponds became nothing more than divots of parched earth. The refreshed pastures will also mean an abundance of hay to feed cattle. Hay was in such short supply last year that prices skyrocketed. Mr. Kirby said he was paying as much as $250 for a ton of hay last year, about two and a half times the normal price.

Still, Mr. Kirby is tempering his excitement. This spring has taught him that the whim that brought moisture could just as cruelly take it back.

“It doesn’t matter how wet it is today,” he said. “We’re just two weeks away from a drought.”

A version of this article appeared in print on June 10, 2013, on page A1 of the New York edition with the headline: After Drought, Rains Plaguing Midwest Farms.